The Laboratory of Hydrology in the Institute of Ecology and Natural Resources of the Academy of Sciences of the Tatarstan Republic monitors 5206 current small rivers, 8000 watershed lakes and 600 ponds within the framework of fundamental and applied scientific research in surface runoff nature and formation conditions at the territory of Tatarstan Republic The following information is entered into the Water Resources Estimation Automated System (DB WREAS): inventory verifications of water objects existence and identification, morphometric parameters shifts when water stream conditions and its formation change, data in water management regimes and water quality as well. The System mentioned allows the input, search, comparison, systematization and archiving the large body of data in water bodies at the republics territory. Assigned tasks impact the program products of information data treatment. The latter unite preassigned directories. The application software based on standard methods of mathematical and hydrological calculations and regional hydrological and water management practices is developed for the mathematical processing of information. The manuscript presents the contents and facilities of DB WREAS application.